Typewriting machine



y 1940- w. A. DOBSON TYPEWRITING MACHINE Filed Nov. 25, 1938 INVENTOR Patented July 23, 1940 UNITED STATES PATENT OFFICE 2,209,222 TYPEWRITING MACHINE Application November 23, 1938, Serial No. 242,013

8 Claims.

This invention relates to line-space and detent-release devices for controlling the rotation of a typewriter platen.

The general objects of this invention are to provide a simple and rugged line-space device particularly adapted for economic manufacture; and to provide a simple device operable to effect both line-spacing and platen detent release in a convenient manner, to be actuable by a momentary finger touch by the typist to accomplish either function.

A further object is to provide a device of this character having a manually actuable member normally operable to rotate the platen in line spacing and adapted to function also, by a simple manipulation, to effect release of the platen detent from cooperative engagement with the platen ratchet wheel, the actuating member, set in detent release position, being readily operated by a flip of the finger to restore the detent to cooperation with the ratchet wheel, whence the member may instantly return to its initial linespacing position in readiness for that function.

Other objects and advantages will hereinafter appear.

In the drawing,

Figure 1 is a fragmentary perspective view of a typewriter platen carriage assembly partly broken away to facilitate illustration.

Figure 2 is a fragmentary front elevational view of the device as shown in Figure 1.

Figure 3 is a transverse sectional view taken on the line 3-3 of Figure 2, showing the line-space and detent release lever in initial position for line spacing.

Figure 4 is a view similar to Figure 3 butshowing the lever in full actuated position at the completion of a line-space stroke, and V Figure 5 is a view similar to Figure 3 but showing the lever in detent-releasing position.

The numeral 6 indicates the usual cylindrical platen carried on a shaft 1, the latter being journaled for rotation in carriage end plates 8, one of which is shown. The platen shaft 1 extends through the end plate 8 and has secured thereon a knob 9 for convenient rotation of the platen in feeding paper into the machine. The hub of the knob 9 abuts the outer face of the end plate 8, a collar III on the shaft 1 being arranged to abut the inner face of the end plate 8. The platen 6 has the usual ratchet wheel II mounted for rotation therewith, the teeth of the ratchet wheel having a pitch equivalent to one or more line spaces, or increments thereof.

1 u A spring detent I2 is secured to a flange I3 of the lug 23.

der a slight initial tension, thus holding lever I6 35 the carriage end plate 8 by a bolt II, the free end of this detent being rounded to form a roll I5 pressed into cooperative engagement with a tooth of the ratchet wheel II. The detent I2 thereby serves to yieldably arrest rotation of the platen to 5 accurately position same for each line-spacing.

A line-space and detent-release lever I6 is mounted for oscillatory and endwise movement on the platen shaft 1, the lever I6 having an elongate aperture Il engaging the platen shaft. As 10 shown more clearly in Figure 2, the lever I6 is disposed adjacent the ratchet wheel II and is guided sidewise by a face of the ratchet wheel on one side, and by the end of collar III at the other side. The lever I6 extends upwardly in an arm 15 I8, the free end of which carries a finger-piece I9 integral with the arm and disposed for convenient access by the typist. v

The lever I6 carries a dog 20 preferably formed by bending an integral portion of the arm I8 20 laterally to overlie the ratchet wheel II. A spring 2| is arranged to yieldably hold the lever I6 in normally ineffective or quiescent position shown in Figure 3, the ends of the spring being attached to a lug 22 on lever l6 and a lug 23 on 25 the end plate 8. Lever I6 is extended downwardly in an arm 24 including a forwardly projecting finger 25 adapted to engage a stop 26 on the end plate 8 when lever I6 is oscillated to rotate the platen in line-spacing. It is to be noted 30 that, with lever I6 in its quiescent position as shown in Figure 3, the lug 22 is in a direct radial line from the platen shaft I projecting through In this position the spring 2| is unin its uppermost position defined by the engagement of the lower end of slot IT with the platen shaft. The tension of spring 2| yieldably holds the lever I6 against oscillatory movement in its quiescent position, in which position the dog 20 0 is disposed just forwardly of the ratchet tooth I la or just above the space in front of said tooth.

Line space rotation'of the platen is effected by a simple manipulation of lever I6 produced by manually engaging the finger-piece I9 and press- 45 mg same downwardly and r'earwardly' or tangential to the platen axis, that is, generally opposite the direction in which the finger-piece faces, this movement causing the dog 20 to first move into the space forward of the ratchet tooth Na and thereafter engage the said ratchet tooth. It may .be here noted that the manual effort in manipulating lever I 6 in its line spacing initial movement is so directed as to overcome the force of spring 2|, and the spring is so arranged as to require the movement of the lever in such direction that the dog 20 is moved directly into the tooth space ahead of tooth ||a. As dog 20 arrives within the tory movement of the lever l6 which causes a' corresponding rotation of the platen, in that the dog 20 is engaged with the tooth Ila. The oscillatory movement of lever I6 is limited by the engagement of the finger-piece 25 with the stop 26,

the angular distance between these elements, with the lever IS in quiescent position, representing slightly more than the usual line space, that is, the spacing between the end of finger 25 and stop 26 is such as to permit oscillation of lever l6 from its Figure 3 position to that shown in Figure 4. ,It will be observed that during line space rotation of the platen the end I5 of the detent l2 snaps into the succeeding tooth of the ratchet wheel to yieldably detent the platen in the new line-space position.

Lever |6 may also be operated to effect -th release of the detent |2 from cooperative engagement with the ratchet wheel II, the end of arm 24 of lever I6 being arranged to engage roll I 5 of the detent l2 and push same to ineffective position as shown in Figure 5, the end of arm 24 having a recess 21 into which the roll l5 seats in its released position. As previously described, lever IB is pressed rearwardly and downwardly to effect line-space rotation of the platen. When release of the platendetent I2 is desired, the lever l6, that is, the finger-piece l9 thereof, is swung forwardly about the shaft 1 until a tip 28 of arm 24 comes into engagement with the roll l5 and cams same outwardly beyond operative engagement with the ratchet wheel With the roll I5 snapped into the recess 21, lever I6 is held in itsdetent-released position as shown in Figure 5. When it is desired to restore the detent to normal cooperation with the ratchet wheel II, a slight rearward flip of the fingerpiece I! is effective to free the end of arm 24 from the roll l5, whence the spring 2| pulls lever IE to its normal quiescent position shown in Figure 3.

Itwill be seen from the foregoing that the invention provides a simple and rugged line-space device as embodied in the lever |5 and associated elements, readily adapted for economic manufacture. It will also be seen that lever l5 may be operated to effect line-space rotation of the platen by a somewhat carefree actuation of the lever in a generally downward andrearward dithe lever, and in either function, spring 2| re-' stores the lever Hiinstantly to its normal quiescent position.

While, in this application, there is specifically described one embodiment which the invention may assume in practice, it will be understood that same is shown for the purposes of illustration, and that the invention may be modified, and

embodied in various other forms without departiing from its spirit or scope as defined in the appended claims.

What is claimed as new is:

1. In a line-spacing mechanism for typewriters having a rotatable platen and a ratchet wheel rotatable therewith, in combination, a lever mounted for pivotal and endwise movement about the ratchet wheel axis and having a finger-piece at one end, a dog fixed on said lever to cooperate with said ratchet wheel, means for limiting the swing of said lever in line-spacing direction, and spring means acting upon said lever to yieldably resist pivotal and endwise movement thereof with said dog in initial line-spacing position free of said ratchet wheel; whereby actuation of said lever finger-piece moves said dog into coaction with said ratchet wheel to rotate the platen a predetermined extent in line spacing.

2. In a line-spacing mechanism for typewriters, the combination with a rotatable platen, a platen shaft, and a toothed wheel rotatable with said platen, of a lever having an elongate slot bearing onsaid shaft and forming a fulcrum for said lever permitting endwise and oscillatory move- 1 ment of said lever, a dog carried on said lever and movable therewith to cooperate with said toothed wheel, means limiting oscillatory movement of said lever to restrict movement of said dog to substantially a tooth pitch, and a tension spring acting upon said leve'r at a point in line with the longitudinal center of said slot to yieldably resist oscillation of said lever to either side of said line.

3. In a line-spacing mechanismfor typewriters having a rotatable platen and a ratchet wheel rotatable therewith, in combination, a lever having a movable fulcrum at the ratchet wheel axis and projecting upwardly therefrom carrying a finger-piece at its upper end, a dog fixed on said lever intermediate the fulcrum and said fingerpiece to cooperate with said ratchet wheel, means for limiting the swing of said lever in line-space direction, and a tension spring-acting upon said lever to yieldably resist pivotal and endwise movement thereof and yieldably hold said dog in ini-, tial line-spacing position free of said ratchet wheel; whereby a downward and rearward pressure on said lever finger-piece tangential to the platen axis' against the tension of said spring moves said dog into engagement with said ratchet wheel to rotate said platen a predetermined extent in line' spacing. e

- 4. In a line-spacing mechanism for typewriters having a rotatable platen, a shaft therefor and a ratchet wheel rotatable with said platen,jin combination, a lever having a finger-piece at one end and having an'elongate slot bearing on the platen shaft, forming a fulcrum for said lever V permitting pivotal and endwise movement thereof, a dog fixed on said lever to cooperate with said ratchet wheel, a tension spring acting upon said lever to bring one end of the slot thereof against the platen shaft, yieldably resisting pivotal and endwise movement of said leverto hold said dog in initial line-spacing position free of ;-..sai d ratchet wheel, and means for limiting the swing of said lever in line-spacing direction; 1

gential to the platen'aiiis against the tension of said spring moves said dog into engagement with said ratchet wheel to rotate said platen a predetermined extentv in line spacing.

- 5. In a line-space mechanism for typewriters having a rotatable platen, a ratchet wheel rotatw'hereby'actuation of said lever finger-piece tan- 7 able with said platen and a spring detent cooperating with said ratchet wheel, in combination, a line-spacing and detent-release lever pivoted and shiftable at the ratchet wheel axis, a dog carried on said lever which cooperates with said ratchet wheel, means for limiting the swing of said lever in line-spacing direction, and spring means acting upon said lever to yieldably hold said lever in inactive position with said dog in initial linespacing position, said lever including a part movable therewith into releasing engagement with said spring detent; said lever being movable from inactive position against the force of said spring means, in one direction to rotate the platen in line spacing, and in the opposite direction to release said detent, said spring means acting to restore said lever to inactive position.

6. In a line-space mechanism for typewriters having a rotatable platen, a ratchet wheel rotatable therewith and a spring detent cooperating with said ratchet wheel, in combination, a line-spacing and detent-release lever mounted at the ratchet wheel axis for pivotal and endwise movement, a dog fixed on said lever for cooperation with said ratchet wheel, a stop limiting the swing of said lever in line-spacing direction, and a tension spring acting upon said lever to yieldably hold same in inactive position with said dog in initial line-spacing position free of said ratchet wheel, said lever including a part movable therewith into releasing engagement with said spring detent; said lever upon actuation in one direction from the inactive position, against the force of said spring, being movable to rotate said platen in line spacing, and in a generally opposite direction to release said detent, said tension spring acting to restore said lever to inactive position.

7. In a typewriter, the combination with a rotatable platen, a platen shaft, a ratchet wheel rotatable with said platen and a spring detent cooperating with said ratchet wheel, of a linespacing and detent-release lever having an elongate slot bearing on said shaft permitting oscillatory and endwise movement of said lever, a dog fixed on said lever for cooperation with said ratchet wheel, a spring acting upon said lever to yieldably hold said lever in ineffective position, said lever including a part swingable into releasing engagement with said detent, means for limiting the oscillatory movement of said lever, said lever being movable in one direction to bring said dog into coaction with said ratchet wheel to rotate said platen in line spacing, and being swingable in a generally opposite direction to bring said lever part into effective position with said detent, said detent-coacting-lever part pre senting a recess to admit a portion of said detent to yieldably arrest said lever in detent-releasing position.

8. In a typewriter, the combination with a rotatable platen, a platen shaft, a ratchet wheel rotatable with said platen and a spring detent cooperating with said ratchet wheel, of a linespacing and detent-release lever having an elongate slot bearing on said shaft and permitting endwise and oscillatory movement of said lever, said lever comprising an upwardly projecting arm terminating in a finger-piece and having a dog fixed thereto for cooperation with said ratchet wheel, said lever also including a downwardly projecting arm terminating in a recess and adapted to move said detent to released position with the detent seating in said recess, a finger extending from. said lever and adapted to engage a stop to limit oscillatory movement of said lever, a tension spring yieldablyholding said arm in ineffective position; whereby a downward and rearward pressure on said lever arm finger-piece moves said dog into coaction with said ratchet wheel to rotate said platen in line spacing, and a forward pressure on said finger-piece swings said arm into detent-releasing position.

WILLIAM A. DOBSON. 

